Method of sinking molding tubes for concrete piles molded in the ground



1932- E. FRANKIGNOUL 1,872,635

METHOD OF SINKING MOLDING TUBES FOR CONCRETE FILES MOLDED IN THE GROUNDFiled Aug. 24, 1931 4 Sheets-Sheet l Aug. 16, 1932. E. FRANKIGNOULMETHOD OF SINKING MOLDING TUBES FOR CONCRETE FILES MOLDED IN THE GROUNDFiled Aug. 24, 1951 4 Sheets-Sheet 2' L". Finn? zigzwel g- 1932- E.FRANKIGNOUL 1,872,635

METHOD OF SINKING MOLDING TUBES FOR CONCRETEPILES MOLDED IN THE GROUNDFiled Aug. 24, 1951, 4 Sheets-Sheet 5 Fair/{2214 3 Aug. 16, 1932. E.FRANYKIGNIOUL METHOD OF SINKING MOLDING TUBES FOR CONCRETE FILES MOLDEDIN THE GROUND Filed Aug. 24, 1931 4 Sheets-Sheet 4 j}? I /I I I wa I I II I I I I I I I I l l I Patented Aug. 16, 1932 u 4 a stars) EDGAEJDFEANKIGNQUL, 0F BRUSSELS, BELGIUIYE METHQD 0F SINKING DECELDIIJG EC ELCOl'l't'lEuElTEi FEL'ESEHOLDED IN THE GROUND Application filed'hugust24,1931, Serial No. 559,114, and in Belgium'Aug ust 29, 1930.

According to the-invention described in iatent :Hslfid-ifil, issued June17, 1930, a-

limited quantity of a dry mixture of the constituent parts of theconcrete is lirstintro- 3 duced into the lower part oi the sinking tube;this quantity istransformed by the impact of a freely tailing element,formed like a ram, into the highly compressed plugin the tube and formsa sinking mass. it is therefore essential tor the mass which forms thisplug to be compressible.

According to the improved invention this mass may not for example, beslightly moist, like earth, and may when necessary be mixed with stones.In certain cases it may even be formed solely by stony materials.

As a result of the blows of the ram, which it necessary are struck withgreat force, this 0 mass is so greatly compressed laterally that itforms a plug which adheres by friction to the wall of the tube. Thesubsequent blows struck on this plug which now serves asa sinking massand point causes the tube to be driven into the ground to the desireddepth. The plug which is by degrees more and more highly compressed isperfectly fluid-tight as soon as the first blows of the ram have beenstruck and consequently prevents water so from penetrating into thesinking tube, without it being necessary to employ other means for thispurpose. Y

As soon as the tube has reached the desired depth, according to theimproved invention :10 a sufficient quantity of water is poured in thetube above the plug in successive; charges so that the mass forming theplug will be softened and will no longer adhere so strongto the wall ofthe tube. If this mass contains cement it will become concrete and canbe worked.

The operation of constructing the pile is now commenced. The sinkingtube first of all raised to such a height that the plug can come partlyout of the tube, The ram again enters into action. It is no longeremployed tor sinkin the tube because the latter is held in its raisedposition.

It serves for ramming the mass of con crete which is now engaged, butwhich isbe completely dried, but will,

still soft, so that the greater part otthis mass is driven out of thetube vand compressed against the walls o1 the ground below the tube.

The plug, which inyth'e vfirst place served as a sinking'body, will thusbecome finally, part of the base of the concrete pile to. beconstructed. During this period, a partof the lug will. remain inrthe'tubeinorder to make it fluid-tight, that is to say iii-order toprevent water and mudlentering the lower-end of the tube.

After this, concrete let downwith the necessary quantity ot-"water isthen poured. in successive stakes intothe sinking tube r-eachchargebeing driven, rammed or forced down bythe action oftheram, sothat thepile' is completed with the same concrete in the known manner by rammingit layer by, l'ayer and, suitably withdrawing thetu'be-each time.

The complete. method for sinking the tube and subsequently constructingthe concrete piie molded in "the ground hereinafter described withreference to the diagrammatic figures shown in theaccompanyingdr'awings, in which: i i r Figure 1' is a diagrammatic viewshowing the initial arrangement of the tube, plug-and ram.

Figure 2 is a similar view showing the initial driving action of the ramand the utilization of the plug under. the influence of: the ram as ameans r'or forcing the tube into theground. I

Figure 3 is a similar view showing the tube completelyv forced to. itslowermost position by the action of the ram on the plug.v

Figure d is a similar view showingrthe tube and plug in the positionsimilar to Figure- 3, water having been introduced into the tube tosoften the plug.

Figure 5 is a similar view showingthe soft-i ened plug partly drivenfrom the end of the tube and into the ground, the tube having beenslightly raised Figure 6 is a similar view showing the continuation ofthe process by the addition of material within the tube and thedisplacement of thismaterial through the tube to form a.

part of the initial plug material, the tube having been further raised.

Figure 7 is a view of the completed pile following successiveintroductions of material, ramming actions by the ram, and subsequentraising movements of the tube until the material reaches the surface ofthe ground and the tube has been completely withdrawn.

Figure 8 is a diagrammatic view illustrat ing the application of theprocess for the driving of an inclined pile.

Figure 9 is a view of an inclined pile completed in accordance with theprocess.

Figure 10 is a side elevation of a pile driver for driving inclined pilein accordance with the process.

Figure 11 is a perspective view of a pile reinforce used in connectionwith the process.

Figure 12 is a plan view of the same.

Figure 13 is an enlarged broken sectional view showing the means forconnecting the uprights and helical member making up the reinforce shownin Figure 11.

Figure 14 is a view in elevation of a modified form of reinforce.

Figure 15 is a plan of the same.

Figures 16, 17, 18, 19 and 20 indicate successive stages of a pileconstructed in accordance with the present process and employing arecess, Figure 20 indicating the completed pile.

Figure 21 shows a reinforced concrete sinking head used in connectionwith the process.

Figures :22 to 27 inclusive show successive steps of the process whereinthe sinking head is employed in connection with the formation of thepile, Figure 27 showing the completed pile.

As the initial step in the process, a limited quantity of a mixture'ofconcrete (cement, sand or quarry dust, gravel or stones, etc.) or amixture of stones with or without a binding agent is introduced into thelower part of a hollow form or tube (a) (Figure 1).

The mixed mass, which may be dry or slightly moist, is subjected to theblows of a ram b) (Figure 2) until the fluid-tight plug (a) is formed inthe lower part of the tube, serving as a sinking body and point onaccount of its strong frictional adherence to the wall of the tube.

Under continued successive action of the ram on the plug, the tube (a)by reason of the adherence between the plug and tube is finally driveninto the ground to the desired depth, as indicated in Figure 3.

Water for softening the plug is then intro duced and, after the tube hasbeen suitably raised and held against further downward movement, theplug (a) is detached from the wall of the tube by repeated actions ofthe ram (1)) and is partly driven out of the tube and stronglycompressed against the wall of the space formed in the ground below theraised tube (a) (Figure 5). Successive char es-of concrete are poured inthe tube and rammed by means of the said ram, in order to form the bodyof the pile, by compressing the concrete layer by layer in order topress the concrete down in the ground until the body of the pile hasbeen completed, it being understood that the tube is progressivelyraised to permit the formation of the pile beneath it.

The ram Z), falling freely, thus serves successively for the formationand for the compression of the plug 0; for sinking the tube by means ofthis plug; for expelling the plug from the tube into the ground afterthe addition of water; for ramming and compressing layer by layer themass of concrete poured in successive quantities into the tube until thepile is completed.

According to the improved invention, it is important for the diameter ofthe ram 5 to be substantially less than the internal diameter of thetube and also for this ram to be given a frusto conical or similar shapeat the lower part so as to accelerate the formation of the plug andincrease the frictional adherence of the latter in the tube.

The above features, which characterize the improved method for theaccelerated sinking of a tube in the ground by means of a ram having atapered head and the diameter of which is substantially less than thatof the tube, are of quite special importance and ad-- vantage forpermitting the rational, ra )id and economical construction of inclinedcon crete piles molded in the ground.

Up to the present time it has never been possible to construct suchinclined piles rationally, rapidly and economically, on account of theserious difliculties arising from this very inclination.

With the usual methods, the ram, which is always of considerable weight,encounters a considerable frictional resistance in sliding within theinclined sinking tube. Its kinetic beating and ramming energy is as aconsequence considerably reduced and is further reduced by an increasinginclination of the tube. Moreover, the sliding friction of this ramagainst the wall of the tube causes the latter to be rapidly worn.

Moreover, this ram slides eccentrically in the tube unless complicatedand costly means are provided for ensuring a concentric guidance.Further, such means-can no longer be employed when constructing inclinedreinforced concrete piles.

The particular method for the forming of inclined piles will bedescribed with more particular reference to Figures 8, 9 and 10.

In Figure 8, a is the sinking tube which bears against the inclinedguide track (Z and T is led into a guide ring under the control of acable 7; b is the ram which, when outside the tube a, also bears uponthe inclined guide track (Z and is operated by means of the cable palemons Thisyram has .a conical head a which is 'not customary for ramsusually employedinsinking tubes.

According to the improved method this ram is employed for the. formationof the concrete plug 0 in the lower part of the tube a, for s1nkin thetubelby strikingthis plug, for

expelling the plug from the tube when the latter has been driven intothe desired depth, forconstructing the enlarged base 0 of the pilev inpart by means of this plug and for ramming successive charges ofconcrete poured into the tube a for forming the body j ofithe'pile.

When the ram a-descends along the guide d, its position is naturallyeccentric with respect to the tubea the internal'diameterof which issubstantially larger than that of the ram.

The lower end of this ram then encounters, by means of its conicalsurface 6, the upper edge a of the tube a, the efiect of which is toalter the direction of descent of this ram and make it follow a pathwhich very closely approaches the axis of the tube a, so that the saidram, during its travel inside the tube, remains approximately on theaxis of the tube without being in frictional contact with the wall ofthe latter.

As a consequence the considerable loss of speed and kinetic energy ofthe ram on ac count of the usual friction with the inner wall isavoided.

The pathof the ram inside the tube is obviously not absolutelyrectilinear and does not follow exactly the axis of this tube, but it isan extremely flat curve so that the ram does not touch-the wall of thetube.

It is quite easy to distinguish the ringing sound produced by the ramwhenit enters the tube and the dead sound when the ram strikes theconcrete .at the bottom of the tube,.bnt no noise produced by frictionagainst the wall of the tube can be noticed.

According to the diameter, the length and the inclination of the tube,the height'of fall of .theram and if'necessary its angle of conicity canbe varied, the latter by providing removable heads of different tapers,

i so that in all cases the sliding friction in the tube and theresulting loss of energy will be avoided.

It is observed in practice that the loss of energy due to the impacts ofthe conical head of the'ram against the upper edge or the tube ispractically negligible.

Approximately the same rapidity of sinking of the tube, the samecompression of the soil, and the same compression of the concrete areobtained for constructing the pile with identical heights of fall andweights of the ram, whether the tubes are vertical orinclined.

The invention also provides for the ram to be guided if desired outsidethetube in sition of the tube will not present any serlous objection.

.The presence of the well known basket frame inside the tube will notprevent the ram from penetrating into this basket in order to force thesuccessive charges of concrete into it and centre the basket perfectlyinside the tube. It is sufficient to employ a ram of suitable diameter,that is to say substantiallyless than that of the basket, exactly as inthe case of a vertical reinforced pile. V

The centering of the basket is improved in the case of baskets employedfor reinforcing the upper part of the pile, which is generally the casein practice.

It is also to be noted that the impact of the ram on a plug formed inthe lower part of the inclined tube facilitates the sinking of this tubeand preserves much better the direction and inclinationof the sinkingthan if the tube were sunk by the usual method by striking on its upperedge.

Moreover, the breaking up of the ground is much less noticeable.

Finally, the fact that the ram acts concentrically in the inclined tubeforramming and for driving the concrete out of the tube during the wholeperiod of construction of the pile ensures a uniform compression ofground and a maximum strength of the pile.

It has been found that all the ei'lects and. advantages described aboveare obtainable at all the inclinations necessitated by the requirementsof practice.

The pile driver shown in Figure 10 is arranged for sinking tubes andconstructing piles at all inclinations.

It is also suitable for'constructing vertical piles.

This pile driver comprises the] post it u on which are provided thetracks and iding means for the tube a and the ram 6. This post'can beinclined by pivoting about a pin 79 mounted onthe usual carriage 0carrying the machinery. Two supports 2' adjustable in length or inposition at their base 25 by known means permit the inclination of thepost it to be varied and consequently that of the tube and of the pile.The carriage is levelled up and locked in position by any usual'means. I

The invention also provides for the fact that in the construction ofvertical or inclined piles, it is necessary to obtain as far as possiblea considerably greater compression of the ground by considerablyincreasing the force of the blows struck by the ram when ramming theconcrete which is much greater than that considered necessary up to thepresent time, and this as far as the extreme limit.

Gil

This increase in the strength of the blows is also very advantageous inthe formation of the concrete plug and when sinkingthe tube, so that itaccelerates the work and improves the general result obtained from themethod.

The compression of the ground which is caused by the sinking of the tubedepends essentially on the diameter only of this tube; the increase inthe force of the blows struck by the ram only serves in this case toaccelcrate the formation of-the concrete plu and the sinking of thetube. But it is otherwise with the influence which tne force of theblows of the ram exerts on the compression of the ground by the rammingof the concrete during the construction of the pile.

Up to the present time this force of impact has been chosen solely witha view to obtaining the pressure which is thought necessary for ramming,without wishin to exert any particular influence on the compression ofthe ground.

One of the features of the invention con sists in considerablyincreasing the force of the blows when ramming so as to obtain not onlya much greater compression. of the ground but also a considerableimprovement in the quality of the concrete pile.

The increased compression of the ground is due to the fact that whenramming with considerable kinetic energy a succession of annularprojections are formed on the surface of the pile which transmit thepressure of the ramming action to the ground in a ra dial direction;these projections, after hardening, exert compression in the axialdirection of the pile.

Vhen the force of these blows is considerably increased. each projectingring spreads rapidlyin a radialdirection and can thus harden morequickly, so that it acts on the ground, in the neighbourhood of thepile, almost like a rammer working on this ground and the increase inthe force of the blows struck thus produces a considerably greatercompression of the ground around the pile.

This increase in the force of the blows eX- erts no unfavourableinfluence on the quality of the pile. In fact, the increased radialspreading of the concrete, in the form of projecting rings or flanges,prevents this concrete from being exposed to an excessive pressure whichwould cause it to harden immediately. It is exposed solely to a pressurewhich exerts the best influence for producing a rapid hardening bynormal means.

The disadvantages whicn may result from blows struck with great force onthe upper edge of the tube, for sinking the latter, are here, as alreadystated, considerably reduced on account of the fact that these blows arestruck on the plug at the base of the tube as above described.

In order to give a concrete example, the following figures will begiven:

Internal diameter of the tube500 mm.

Weight of freely falling ram3000 kgs.

Height of fall4 to 6 metres.

Pressure of blowsl2,000 to 18,000 kgs.

Under a test load of 250 tons, the pile con structed in accordance withthe data given above sank only 2 mm., while for a similar pileconstructed with a force falling within the usual limits, the sinkingresulting from the same load is several cms. at least.

It can be estimated that according to the invention the blows are struckwith a minimum force comprised beween and 90 kgs. per cm Another featureof the improved invention is that it makes it possible to constructrationally reinforced concrete piles molded in the ground by ramming theconcrete.

The fact that the high compression of the concrete in the ground andconsequently the high compression of the ground require the use of a ramof substantially smaller diameter than that of the tube, permits thisram to be made to descend easily in the interior of a basket frameforming a hollow perforated cylinder constituted of axial bars connectedto each other by a round iron bar wound helically over the whole height.

The straight bars, forming the generating lines of the cylindricalbasket lowered into the tube, may be arranged at a small distance fromthe wall of this tube and consequently from the wall of the holehollowed in the ground by this tube, that is to say in the ef fectivereinforcing zone of the pile.

On account of the high compression of the ground which may be producedin this zone by the very firmly rammed concrete, the said bars and theirhelically wound connecting framework, are completely enclosed by highlycompressed concrete and consequently work under the best conditions forgiving the pile a maximum strength.

This detail of the process will be described with more particularreference to Figures 12 to 20. V i

In Figures 11 to 13 the longitudinal bars are formed by flat ironmembers we connected together by a round iron member n (wound helically)passing through notches in the bars m.

In Figures 14 and 15 the longitudinal bars are formed by round ironmembers m which are connected to the helically wound iron members at byiron wire connections 1".

In order to construct the piles shown in Figures 16 to 20 the tube isfirst of all driven in and its base is formed in the ground by a mass oframmed concrete comprising the expelled plug. The cylindrical basket nmis then lowered into the tube, leaving a small free space between itselfand the wall of the tube (Figure 17).

nemesis A mass of fresh concrete is then introduced. into the basket upto a predetermined height so that the lower part of the basket isembedded in the mass of fresh concrete (Figure 18).

The ram 6 then acts in the interior of the basket (Figure 19) in whichit can descend easily by virtue of its tapered point e; and it rams theconcrete while forcing it laterally when the tube a has been raisedsufliciently for the mass of concrete situated below it to be spread outand compress the ground while enclosing under high pressure theframework of the basket the longitudinal bars of which bear on theenlarged highly compressed face of the pile which is shown in thecompleted state in Figure 20.

The same basket framework can be employed for inclined piles as statedabove, with the same advantages as for vertical piles.

The improved invention finally provides for the case when the concreteplug formed at the lower part of the tube and constituting a sinkinghead for the latter encounters at a certain depth a layer of groundoffering an unexpected and extraordinarily high resistance.

When such a case occurs, the sinking tube with the concrete plug must becompletely removed and replaced by another tube provided at its end witha sinking point permitting the resistance of the layer to be traversedto be overcome.

The improved invention allows the work to be continued with the sameinitial tube by placing then above the concrete plug an extremely strongpoint upon which the blows of the ram are struck at the same time as acertain quantity of water is poured in in order to soften the plug andexpel it from the tube.

A new plug of concrete is then formed by ramming over this point andthis new plug, under the efiect of the ram, continues to carry the tubeinto the ground to the desired depth.

Figures 21 to 27 illustrate by way of example this improved mode ofsinking by means of a free pointed head in the tube and a concrete plugformed below it in this tube.

The pointed sinking head shown in Figure 21 consists of aconical-cylindrical body 4) formed of reinforced concrete andterminating at the lower part in an iron or steel point 8.

When it is observed that the sinking of the tube by means of theconcrete plug can no longer be continued on account of the presence ofextraordinary obstacles (Figure 22) the ram 2) is removed and theconcrete body o provided with the iron point 8 is inserted in the tubeand rests upon the concrete plug 0 formed in the lower end of thelatter.

Then, by means of light blows on the body '0 with the ram, the point 8is made to penetrate into this plug which is softened with water (Figure23) (Figure 23) concrete a which is intended to form anew concrete plugis rammed. I

.TlllS mass it protects on th-eonc handthe reinforced concrete body 4)from the blows of the ramwhile providing afluid-tight joint preventingthe entry of water from the ground, 1

7 By continuing to strike on the plug a the tube a continues to bedriven in (Figure25) the pointed body a expels the initial con.- creteplug 0 below thetube and spreads it out in the ground laterally belowthe tube so that, the iron point 5 upon which-the ram crintinues to actthrough the new concrete pug which are displaced by the sinking body 4;inorder to permit the driving of the tube to be continued down to thedesired depth (Figure 26;). i

Finally the tube is gradually withdrawn from the ground in the knownmanner and the concrete pile is constructed in the manner indicatedabove, by ramming successive chargesof concrete poured into, the tubeduring the gradual withdrawal of the latter until the pile is finallycompleted, the sinking points c 8 remaining in the ground.

Claims. H 1. Method of constructing concrete piles molded in the groundby means of a pipe temporarily sunk to the desired depth, in accordancewith the principal patent, comprising in combination: the formation of aslightly moist concrete plug at the lower part of. the pipe, the use ofa ram, the diameter of which is substantiallylessthan that of theterminating below 1n a trunconic portion, the use of this ram tocompress said plug, to drive in the pipe by direct impact on this plug,for expelling said plug and for ramming the concrete of the pile, theaddition of water after driving in the pipe tofacilitate the expulsionof the plug, the use of means to guide the ram at an inclination, andmeans to overcome abnormal resistance of the ground.

2. Method according to claim 1 for constructing inclined concrete pilesmolded in the ground, comprising in combination the guiding of thesinking pipe on an inclined path with slight frictional resistance, theguiding of the ram on this same path during its movement outside thepipe, the use of a ram with a trunconic head, intended to divert thedirection of descent of the ram when this latter meets the upper edge ofthe pipe, and the use of means to modify the deviation of the ram, andmeans to overcome abnormal resistance of the ground.

pipe. and

After this a sufficient. quantity of dry or slightly moist concrete orisintroduced into the tube 0b. above the holy 2) after which thisquantityvof,

a traverses the extraordinary obstacles 3. Method according to claim 1,for constructing inclined concrete piles, comprlsmg 1n combination theguldmg of the sinking pipe and of the ram with trunconic head on aninclined path having slight frictional resistance, the arrangement of anarmature, forming a cylindrical, large mesh basket, in the pipe, the useof means to modify the deviation of the ram when it meets the upper edgeof the pipe, and means to overcome abnormal resistance of the ground.

4. Method according to claim 1, for making inclined concrete pilesmolded in the ground, comprising in combination the guiding of thesinking pipe and of the ram on an inclined path having slight frictionalresistance, the use of a ram having a trunconic head which is removableand adapted to be replaced by another of different conicity, and meansto overcome abnormal resistance of the ground.

5. Method according to claim 1 for making concrete piles molded in theground, com prising in combination, the introduction of the plug fromabove into the pipe, an auxiliary sinking member having a pointed end,the formation of a second plug above the auxiliary driving member, byramming a mass of slightly moist concrete, and sinking the pipe bydirection impact of the ram on said second plug.

6. Method according to claim 1 for constructing concrete piles molded inthe ground, comprising in combination, introducing into the pipe, abovethe sinking plug, a cylindrical concrete driving member terminating in ametallic point, the formation of a second plug by ramming slightly moistconcrete above the auxiliary driving member, and driving in the pipe bydirect impact of the driver on said plug.

In testimony whereof I aflix my signature.

EDGARD FRANKIGNOUL.

